Modern radio communication systems are under pressure to provide faster data rates. One technique for using the transmission channel to increase data rates is based on the use of multiple antenna systems. Multiple antenna systems are typically known as Multiple Input, Multiple Output (MIMO) systems.
Radio communications can be improved using different diversity modes. Different diversity modes include time diversity (different timeslots and channel coding), frequency diversity (different channels, spread spectrum, and Orthogonal Frequency Division Multiple Access (OFDMA)), and also spatial diversity. Spatial diversity may be implemented though MIMO techniques in which multiple antennas are used at the transmitter or the receiver end. MIMO technology can also be used to increase the data rate (spatial multiplexing).
Long Term Evolution (LTE) Advanced-based communication systems are defined to include a number of antenna ports. In LTE, an antenna port may refer to a logical port that is used to control one or more physical antenna elements.